Text 353, 272 rader
Skriven 2004-10-09 06:36:00 av Lennart Kiil (1:278/230)
Ärende: Re: Interview with Mayr
===============================



"Tim Tyler" <tim@tt1lock.org> wrote in message 
news:ck6ces$34p$1@darwin.ediacara.org...
> Lennart Kiil <kiilx@xtele2adsl.dk> wrote or quoted:
>> "Tim Tyler" <tim@tt1lock.org> wrote in message
>> > Lennart Kiil <kiilx@xtele2adsl.dk> wrote or quoted:
>> >> "Tim Tyler" <tim@tt1lock.org> wrote in message
>> >> > Michael Ragland <ragland37@webtv.net> wrote or quoted:
>> >> >> Michael Ragland <ragland37@webtv.net> wrote or quoted:
>
>> >> >> MAYR: There's absolutely no chance of the human species evolving.
>
> [...]
>
>> >> >> Tim:
>> >> >> Ernst Mayr doesn't have a clue about human evolution :-(
>> >> >>
>> >> >> MR:
>> >> >> How so? I think Mayr was referring to Darwinian evolution.
>> >> >
>> >> > "There's absolutely no chance of the human species evolving."
>> >> >
>> >> > The statement is idiotic.  Does Mayr think all humans have
>> >> > equal numbers of children?  Has he forgotten about the
>> >> > existence of sexual selection?  What on earth is he thinking of?
>> >>
>> >> Not so fast. That fact that not all people have equal numbers of 
>> >> children
>> >> does not necessarily warrant evolution, especially not in any 
>> >> directional
>> >> sense. Such a claim relies on the premise that on average there is 
>> >> some
>> >> kind of correlation that connects the people having more children
>> >> with a certain genetic makeup.
>> >>
>> >> The same basically goes for sexual selection.
>> >
>> > That doesn't make the statement that we are not evolving any less
>> > stupid.
>>
>> I agree that Mayr far overstated the case when saying
>> "There's absolutely no chance of the human species evolving."
>> This statement borders on the absurd.
>>
>> What I was objecting to was your inference from differential reproductive
>> output to evolution.
>> Here is why, imagine we now live in an environment where number of 
>> offspring
>> relies more heavily on choice and not so much on natural capability. This
>> would reduce the correlation between reproductive succes and genetic
>> evolution because there might not necessarily be any segmented genetic
>> composition to the people choosing to have more children.
>
> My questions to Mayr were rather rhetorical - and aimed at suggesting
> what factors Mayr might have missed.
>
> Even without differential reproductive success, you can't avoid
> evolution in practice - due to genetic drift.

This is true, of course, but I think it was implied that what was under 
discussion was evolution in a directional sense.

>
> In fact, differential reproductive success will always decrease the
> effective population size - and will thus increase the magnitude of
> the effect of genetic drift on gene frequency changes.

Yes, this is also completely true, no argument here.

>
> In an environment like ours - where individuals choose other individuals
> on the basis of their attractivness, resistance to diseases and worth as
> potential mates - and the environment is full of selection pressures very
> different from the one the species evolved in - differential reproductive
> success is practically bound to result in gene frequency changes.

I remain convinced that the connection between the genotype and the realized 
phenotype is more obscured in modern society than earlier hence selection 
works less efficiently on the genetic level.

>
>> For example I live in Denmark where we have the socalled wellfare state.
>> This basically means that the burden of having children has been 
>> distributed
>> over society at large. This means that anyone, regardless of their 
>> natural
>> potentials can have a lot of children. [...]
>
> Welfare suddenly makes the whole society more abundant?  I would expect
> the average number of children in each generation to be roughly unchanged.

No, in fact the number of children born decreases substantially. The 
population size may still increase though since now most individuals survive 
to reproduce regardless of their genetic makeup, another indicator of 
reduced effectivnes of natural selection. My point though was that the 
correlation between genetic fitness and realized fitness is obscurred.

>
>> This renders the whole idea of selection obsolete.

Okay, admittedly an overstatement from my side. It has got more to do with 
me generel view of selection as a bad metafor since it indicates reasoned 
choice (intention) in a purely causal process. Actually selection is a 
better metaphor now that we have reached a point where we actually can 
select. Another long discussion about the transistion from causal to 
reasoned proces.

> No - you must be kidding.  Welfare only redistributes material resources.
> It doesn't dictate who gets to mate with whom.  Females will still
> get competed for.  What will actually happen is the practically the
> reverse - welfare creates a different environment - a whole bunch
> of strategies that used to work no longer pay off - and an whole
> bunch of new strategies are needed.

Ok, here lies the potential for a really long and important discussion. Do 
you mind if we start another thread dedicated to this one?

>
> Welfare exists in my country as well - but it makes no serious attempt
> to offer everyong equal resources - it's main function seems to be to
> prevent screwed-up individuals dropping off life's ladder too prematurely
> in a manner that wastes the resources the government invested in their
> education.

Hmm, I wonder if politicians really think like this?!

>
>> Natural selection because natural potentialities are
>> leveled out by governmental redistribution.
>
> So: in Denmark, all women are equally beautiful - and all men are
> equally rich?  I would suggest that in fact the ground is not
> /actually/ that level over there.

Well, they are becoming more equally beautiful by the day. Another modern 
invention to obscure the relationship between the genotype and the phenotype 
is plastic surgery (though I still pride myself on being able to spot the 
naturals). These days you do not necessarily get what you bargain for.

And yes, most men are more or less equally rich.

>
>> Sexual selection because the obligation to help women support children
>> has been tranfered from the individual man to the state. In short
>> contingency and randomness is becoming relative more important than
>> more deterministic forces now than earlier in history. Thus I do not
>> agree that evolution (in a directional sense) occurs faster in humans
>> now than earlier, quite the opposite.
>
> I would suffix that whole sentence with "in Denmark" - or you have a
> ridiculous syllogism on your hands.

True enough, and maybe I am mistaken in using Denmark as an example if it is 
really not that representive of the generel world trend.

>
>> > There's a reasonable book-length treatment putting the case for humans
>> > evolving in modern times faster - if anything - than before - due
>> > to being in an environment which is different from the one they
>> > evolved in - and because the difference in reproductive success
>> > between the most successful reproductives and the least in modern
>> > times is likely greater than at any point in history - i.e.
>> > the Guinness record holders for offspring lived rather recently.
>> >
>> > The book is: "Children of Promethius" - by Christopher Wills.
>>
>> As noted above, it does not sufice that the environment is merely 
>> different
>> to indicate more evolution, the environment has to be conducive of
>> directional evolution for this argument to hold. That is, it has to be an
>> environment that makes genes visible to selection. Modern society more 
>> than
>> anything obscures the genetic component.
>
> Cultural evolution is the main motor driving genetic evoultion these
> days.  The breakneck speed of cultural evolution radically transforms
> the environment in mere decades.  Genes and culture co-evolve - and
> so genes are dragged along for the ride.  The ride genes are on
> is definitely accelerating - with sexual selection and genetic
> engineering looking as though they will become dominant forces
> in the arena of nucleic-acid-based genetic change.

Yes the ride is accelerating, but still, that does not invalidate my 
fundamental insight that for this to have any consequence in darwinian 
evolution you need a rigid relationship between some genes and whatever 
realized phenotypes are currently in fashion.

>
>> >> > As for speciation, it seems *highly* likely that strains of
>> >> > asexual human clones will arise in the near future. [...]
>> >>
>> >> what is your concept of 'near future'?
>> >
>> > The first human clones?
>> >
>> > Cloneaid says they have 13 cloned human babies so far
>> > [on http://www.clonaid.com/news.php].
>> >
>> > I don't know if that is true - but at least that number of
>> > human clones will probably exist by this time next year.
>>
>> Ahh ok, by asexual clones I thought you meant clones that could actually
>> reproduce asexually like parthenogenetic strains in some animals, this is 
>> an
>> entirely different matter.
>
> Many of the early clones will be clones of infertile individuals for
> which cloning is the only possible chance of reproduction.
>
> If these individuals don't clone themselves they can't have babies - and
> many of them find that frustrating.  Obviously if they /do/ clone
> themselves their descendants are highly likely to inherit their
> infertility - and are likely to find themselves in exactly the same
> position - clone or die.
>
> So - many of the very first human clones will effectively be
> parthenogenetic strains - who can only reproduce by cloning themselves.

Hmm, raises some ethical issues. I am glad that we are already to many 
people on this earth, otherwise the perspectives for men looked pretty bleak 
;-)

>
>> And it is going to be a while before clones start to matter in the global
>> household, compare:
>> 13 : 6,400,000,000
>
> How long will it be until clones matter?  Obviously a generation or so
> at least.

Obviously a lot more.

>
> I forsee at least two avenues for clones establishing themselves.
>
> One is the cloned celebrity.  Celebrities are naturally in demand -
> it only makes sense for there to be more of them to go around.
> Celebrities will be cloned by the celebrities themselves, to reduce
> some of the risks associated with them dying - and losing the franchise
> associated with their identity.  Celebrities are also likely to be cloned
> with or without their permission - by individuals who love them and want
> to form closer associatons with them.

But they are in demand precisely because they are rare. We are now changing 
the topic into market economics (which in fact might not be off the track).

>
> The other is cloned individuals to play specialised roles.  At least
> some cultures will have no qualms about producing humans with genetic
> specialisiations to fill particular roles in society.  Some of the
> individuals will most likely be sterile clones.  Cloning will be basically
> done for the same reason that Ford cars are mass-produced in identifiable
> models - the behaviour of the results is known through testing, you don't
> have to offer technical support for multiple models, employers can read
> reviews of the model by other customers and know what they are getting,
> and R&D costs are minimised.
> -- 

So I supose the road to hell really is paved with good intentions

Best regards,
Lennart Kiil
www.zensci.com
---
ū RIMEGate(tm)/RGXPost V1.14 at BBSWORLD * Info@bbsworld.com

---
 * RIMEGate(tm)V10.2á˙* RelayNet(tm) NNTP Gateway * MoonDog BBS
 * RgateImp.MoonDog.BBS at 10/9/04 6:36:28 AM
 * Origin: MoonDog BBS, Brooklyn,NY, 718 692-2498, 1:278/230 (1:278/230)